76376-98-2Relevant academic research and scientific papers
Lewis acid-promoted stereoselective Diels-Alder cycloadditions of captodative olefins acetylvinyl carboxylates and NMR structural study of their cyclopentadiene adducts
De Alba, Octavio Garcia,Chanona, Jorge,Delgado, Francisco,Zepeda, Gerardo,Labarrios, Fernando,Bates, Roderick W.,Bott, Simon,Juaristi, Eusebio,Tamariz, Joaquin
, p. 108 - 117 (2007/10/03)
A study of Lewis acid-promoted Diels-Alder cycloadditions of the captodative olefins 1-acetyl vinyl carboxylates 1 with cyclopentadiene is described. Catalyst, temperature and solvent were the assessed variables, the exo/endo ratio being more significantl
Diels-Alder Approach to Bicyclic α-Hydroxy Ketones. Facile Ketol Rearrangements of Strained α-Hydroxy Ketones
Creary, Xavier,Inocencio, Pamela A.,Underiner, Ted L.,Kostromin, Ray
, p. 1932 - 1938 (2007/10/02)
The trimethylsiloxy-substituted dienophiles 1-benzoyl-1-(trimethylsiloxy)ethylene, 6, 1-carbomethoxy-1-(trimethylsiloxy)ethylene, 12, and 1-acetyl-1-(trimethylsiloxy)ethylene, 4, all reacted with cyclopentadiene to give adducts in which the carbonyl containing substituent of the major product occupied the exo position, in violation of the Alder rule.Desilylation of the Diels-Alder adducts of cyclopentadiene with 4 and 6 led to ring-expanded ketol rearrangement products on silica gel chromatography.This facile rearrangement was attributed to relief of strain in the star ting α-hydroxy ketone.Equilibration studies showed that in the rearranged 2-hydroxy-2-substituted bicyclooctan-3-one systems 24 and 30, the more stable isomer is the one in which the phenyl or methyl substituent is in the axial position.The presence of a strong intramolecular hydrogen bond of the equatorial hydroxyl group with the carbonyl group accounts for the greater stability of 24 and 30.Acetolysis of endo-2-benzoyl-exo-2-norbornyl mesylate, 2, occurred readily, giving mainly the rearranged product of internal return, 1-benzoyl-exo-norbornyl mesylate, 38.The high reactivity of 2 relative to the endo analogue and the α-H analogue was attributed to some transition-state carbonyl conjugation with the incipient α-keto cation center as well as possible neighboring ?-participation and/or steric rate enhancement.
CATALYZED CYCLOADDITION REACTIONS OF α-SILYLOXY-α,β-UNSATURATED KETONE AND ALDEHYDE
Sasaki, Tadashi,Ishibashi, Yukio,Ohno, Masatomi
, p. 1693 - 1696 (2007/10/02)
The reactions of α-silyloxy-α,β-unsaturated ketone and aldehyde with diene afforded and cycloadducts respectively in the presence of a catalyst.
